BEP44 is an extension to the bittorrent protocol that turns the DHT into a key/value store with the option for mutable content. Instead of the key as the hash of the content as with ordinary info hashes, BEP44 allows keys to be the hash of an ed25519 public key with arbitrary 1k signed content.
However, this protocol extension introduces new problems. An attacker can identify a hash they want to disrupt and generate nearby hashes so that responsibility for a hash moves onto nodes the attacker controls. This attack is addressed in dht_sec, but there is no analogous protection for BEP44 dht_store keys.
Generating elliptic keypairs is somewhat slow without assistance from a GPU, but it should be possible to disrupt service on a small network with very modest CPU requirements.
In this example we generate keypairs looking for keys that hash to values most closely to
$ node keypair.js 40 & sleep 5m && kill %% && echo  19634 0.9727 3962560c5e0f201d173c5fd338f1f0fbbd7c2ac4 0 0.9883 3d527146aed3f4b9c76112010b254c12fcab6bc4 24 1.5703 406ed05940c4bd7893b77fc8625389e33625d3e2 27 1.7773 40391fb044c56636e89a5406d8e5b7d82c927b22 689 1.9844 400478a6fc4d22240f413390178fd08432f019ff 2795 0.3086 f1e8fd76ac6bb352cd8b1792d22b559f3488091e 21255 70/sec
In 5 minutes we were able to generate a key with a hash that had the same first byte and a second byte that was not very far away at 70 keys per second.
However, BEP44 also includes a salting mechanism for storing multiple values under the same elliptic keypair. With this salting mechanism, we can get around a 1000x speedup compared to generating keypairs:
$ node salt.js 40 & sleep 5m && kill %% && echo  19607 0.4063 d821d0d0d3c691dab9b2433e421b2a70b86f97a3 0 0.9688 38eb190bffe841c7baca8bc1b317060916b3efa5 1 0.9844 44e98350ac4c840a2c70798885bc239b8f1b576c 37 0.9961 3fd35d696ab514efb7d19298b8b1dbcba7f63412 44 1.3945 409b8327b09abbb1b4dc3ec2bdbce877670420b1 484 2.7969 400034031b20cfd5511d9a9a7566cf015279d2e0 571 2.8008 400033ef22256402c186a2dd6d131c9cacc23251 967388 2.8242 40002dc55528042f137bc921c66f25d18dcd5abd 1060360 2.9297 400012574b94f5b90dbbc9b963837c9277c695ed 1271514 2.9922 400002275389b826c037ecc9fd7ce27ed48cc516 1783773 2.9961 400001116229951379aa944d3a5c21c773970c18 2215835 3.2578 400000be1cf827fe09dfc2c069de8cebbedde3c5 3163635 3.7813 40000038c5e92b61336d0e216c9d211707e3b8c7 3258594 0.4688 c88ec634122a8c2706ba71ece227d1b866bef230 18776560 62749/sec
At this rate it would take a small amount of time to completely overwhelm certain targets on a network the scale of bittorrent using a small number of attacking computers.